Control knob for chair tilting mechanism



FIG. 1 is a side elevational view of a control knob for chair tilting mechanism embodying my new design all sides being identical and the mechanism being shown in broken lines for illustrative purposes only;

FIG. 2 is a bottom plan view thereof; and,

FIG. 3 is a top plan view thereof. 

The ornamental design for a control knob for chair tilting mechanism, as shown and described. 